As conventional master input devices of master-slave systems, there have been known devices having similar figures to slave units (see PTL 1, for example).
In a master-slave system of PTL 1, a slave unit is an endoscope including an observation optical system and two treatment tools at a front end surface of a long inserting part, and master apparatus includes: plural joints bringing a corresponding bending portions of the inserting part to perform a bending motion; a handle bringing the inserting part to perform a twist motion through a rotational motion of the handle; and two grips that are disposed at a front end of the handle, having similar figures to treatment tools and being operated by both hands so as to move the two treatment tools.